This article presents a study that examined an innovative short‐term program (two sessions of 3 hr each) for the professional development of teachers. The program design is based on the technique of probing acceptance, which is aimed at investigating student learning processes. It relies on students' evaluation, paraphrasing, and adaptation of information presented during a one‐on‐one interview with defined student‐centered interview phases. During the professional development program, teachers were introduced to a novel learning unit that focuses on the subatomic structure of matter. In addition, the teachers were instructed in how to use the technique of probing acceptance during one‐on‐one interviews to evaluate the concepts of the unit. The rationale of the professional development program is that the preparation and execution of, and reflection on the one‐on‐one interviews based on the technique of probing acceptance should have an impact on dimensions of teachers' pedagogical content knowledge (PCK). Four teachers from one Austrian high school participated in this exploratory study, and each teacher conducted two one‐on‐one interviews with two different grade‐6 students. Postintervention interviews were conducted with all the teachers to document the potential influences on the teachers' PCK. The interviews were transcribed word for word, and a category‐based content analysis was applied to the transcripts. Our results indicate that during the professional development program, all the teachers revisited their existing knowledge about the subatomic structure of matter and left with an enhanced PCK, especially regarding their knowledge of learners and of instructional strategies. Overall, we show the technique of probing acceptance to be a promising tool for short‐term professional development programs, and we suggest that our findings have implications for both professional development designers and educators.